Fabric tensioning means for circular knitting machine



p 1962 H. E. CRAWFORD 3,054,280

FABRIC TENSIONING MEANS FOR CIRCULAR KNITTING MACHINE Filed July 9, 1959I N V EN TOR. Herman 6/010/6/0 A TTOR/VEY United States Patent Ofilice3,054,280 Patented Sept. 18, 1962 FABRIC TENSIONING MEANS FOR CIRCULARKNITTING MACHINE Herman E. Crawford, Kernersville, N.C., assiguor to H.E. Crawford Company, Incorporated, Kernersville, N.C., a corporation ofNorth Carolina Filed July 9, 1959, Ser. No. 825,922 3 Claims. (Cl.66-449) This invention relates to circular knitting machines forknitting ladies sheer stocking fabrics and more particularly to means insuch machines for applying a uniform tension to the fabric duringformation of the stitches thereof.

In circular knitting machines and particularly such machines forknitting stocking fabrics, the fabric as it is knitted is carrieddownwardly away from the needles under tension through the interior ofthe needle cylinder and the completed fabric is dropped or ejected fromthe bottom of the cylinder. In one form of fabric tensioning means thefabric is entrained by an air stream which is directed downwardlythrough a tube stationarily positioned within the needle cylinder.During rotary operation of the needle cylinder, the fabric which rotateswith the cylinder, is drawn by the flow of air against and tends tocling to the inner surface of the tube with the result that an uneventension is applied to the fabric by the air stream. Heretofore, in orderto overcome the tendency of the fabric to cling to the surface of thetube bridge members were provided at spaced points around the innersurface of the tube to deflect portions of the fabric away from the tubeand permit the air flow to engage both inner and outer surfaces of thefabric. However, while portions of the fabric were freed from the innersurface of the tube by the bridge members, the flow of air continued topress the fabric against portions of the tube intermediate the bridgemembers and particularly at points adjacent the stitch drawing camswhich resulted in the drawing of uneven fabric stitches.

It is therefore an object of the invention to provide means in acircular knitting machine for overcoming the above mentioned and otherdifliculties encountered in the use of an air flow for entraining andtensioning stocking fabric knitted on such machines.

Another object of the invention is to provide means in a multifeedcircular knitting machine having a tube through which the fabric isentrained by a current of air, which means acts to deflect the fabricaway from the surface of the tube at a point adjacent to the point atwhich the needles reach their lowest stitch drawing position at each ofthe feeds whereby the air flow exerts a uniform pull on the fabricstitches as they are formed.

With these and other objects in view which will become apparent from thefollowing detailed description of the illustrative embodiment of theinvention shown in the accompanying drawings, the invention resides inthe novel elements, features of construction and cooperation of parts,as hereinafter more particularly pointed out in the claims.

In the drawings:

FIGURE 1 is a cross-sectional view taken through a portion of the needlecylinder of a multifeed circular knitting machine and diagrammaticallyshowing air operated take-up means for tensioning the fabric and fabricdeflecting means according to the invention associated with the take-upmeans;

FIG. 2 is a plan View on an enlarged scale of the needle cylinder shownin FIG. 1;

FIG. 3 is a cross-sectional view on an enlarged scale taken along theline 3-3 of FIG. 2; and

FIG. 4 is a View diagrammatically illustrating the fabric deflectingmeans in relation to the forward stitch drawing cam at each of the feedsof the machine.

Referring to the drawing there is shown a portion of a circular knittingmachine, of the type shown and described in my Patent No. 2,861,440,issued November 25, 1958, for knitting tubular stocking fabrics,including a needle cylinder 10 having slots 11 for slidably mountinglatch needles 12 and jacks 15 (FIG. 1). Associated with the needles 12is a sinker mechanism 16 including sinkers 17 which are mounted in slotsfor radial sliding movement and are operated by cam means (not shown) incooperation with the needles during stitch forming movements thereof.The machine is adapted for twofeed knitting during both rotary andreciprocatory operation and is provided with main and auxiliary knittingstations indicated generally at 20 and 21, respectively; At each of theknitting stations the needles are operated through knitting and stitchdrawing movements by cams diagrammatically indicated at 22 and 25 (FIG.2) earns 25 acting on the needles during rotary and forward orcounterclockwise reciprocatory movements of the cylinder 10 and cams 22acting on the needles during reverse reciprocatory movements of thecylinder. Each of the feeds is also provided with fingers 26 for feedingyarns to the needles.

In order to apply tension to and to draw the fabric downwardly away fromthe needles as it is knitted the fabric is guided into a funnel-shapedend 27 of a tube 30,

the enlarged opening of the end 27 preferably terminating adjacent tothe upper end of the needle cylinder 10. The tube 30 is mounted instationary position in and extends downwardly through the interior ofthe needle cylinder as shown in FIG. 1. The end of the tube 330 remotefrom the needle cylinder 10 is connected to and in communication withthe interior of a collecting chamber or receptacle 31 which is adaptedto receive the completed stocking fabrics. The receptacle is connectedby a second tube 32 to the intake side of a suction type fan 35 which isdriven by a motor 36. The fan 35 is operated to create a flow of airdownwardly through the tube 30 to tension the stocking fabric as it isformed on the needles 12 and to entrain and carry the completed fabricto the collecting receptacle. The receptacle 31 is provided with anopening (not shown) through which the completed fabrics may be removedfrom the receptacle and a door 37 for normally closing the opening.

During knitting of the rotary or run-down portions of the fabric thedownward movement of the air through the tube 30 causes the fabric to bepressed tightly against the inner surface of the funnel-like end 27 ofthe tube and the resulting friction developed between the fabric andtube tends to resist the free movement of the fabric thereby causingimproper drawing of the fabric stitches. Heretofore, arch-shaped memberswere provided at spaced positions around the inner surface of thefunnellike end 27 which acted to lift the fabric from theinner surfaceto permit the air flow to engage both sides of the fabric and to assistthe movement of the fabric downwardly through the tube. However, whilesuch archshaped members did act to deflect the fabric away from spacedportions of the inner surface of the portion 27, the fabric continued toengage the inner surface of the end 27 particularly adjacent to thepoint at which the needles reached their lowest stitch drawing positionthus preventing the drawing of stitches of uniform length.

In accordance with the instant invention, the fabric is deflected awayfrom the inner surface of the end 27 of the tube 30 so that the streamof air not only engages and tensions both inner and outer surfaces ofthe fabric but also acts directly on the fabric at the point at whicheach needle reaches its lowest (stitch drawing) position in drawing anew stitch. The means for this purpose is provided at each of the feeds20 and 21 and comprises an elongated wire bridge member 40 of metal orother suitable material which is secured to the inner surface of the end27 of the tube 30 adjacent to the cam 25 for operating the needlesduring forward movement of the cylinder 10. As shown in FIGS. 1 and 2,one end of the bridge member 40 lies adjacent to the upper edge of theend 27 and the member extends downwardly and at an angle to the verticalcenter of the tube and in the direction of the forward movement of thecylinder 10. From its upper end the member 40 inclines inwardly from theinner surface of the end 27 as viewed in FIGS. 2 and 3 to a leading end41 of a high portion 42 and from the latter the member inclinesoutwardly to its lower point of engagernent with the end 27. As shown inFIG. 2, each member 40 is positioned in the end 27 with the leading end41 of the high portion 42 substantially coincident with a radial line,indicated at 45, extending between the center of the cylinder and a lowstitch drawing face of the cam 25 (FIG. 4).

The relation of the member 40 with respect to the cam 25 at each of thefeeds and 21 is such that as the cylinder 10 and fabric is rotated inthe forward direction the needles engage the cam 25 to start theirdownward stitch drawing movement and the fabric engages and rides up theleading inclined surface of the member 40. As the heads of the needlespass through the previously formed stitches, the fabric reaches theleading end 41 of the high portion 42 of the member 40 and the stream ofair exerts a direct pull on the previously formed stitches to therebymaintain a constant tension on the fabric at the point each new stitchis formed. Further, as the needle cylinder 10 continues its movement inthe forward direction, the fabric rides along the high portion 42 of themember 40 to maintain tension on the new fabric stitches as the needlesrise therethrough for the stitch drawing movement at the next feed ofthe machine.

It will be understood that the improvements specifically shown anddescribed by which the above described results are obtained can bechanged and modified in various ways without departing from theinvention herein disclosed and hereinafter claimed.

I claim:

1. In a multifeed circular knitting machine having a needle cylinderadapted for rotary movement in a forward direction, needles in saidcylinder, means for feeding yarn at each of said feeds, a cam at each ofsaid feeds for operating said needles through stitch drawing movementsduring rotation of said cylinder in said forward direction to form atubular stocking fabric, a stationary tube within said cylinder, andmeans for creating a flow of air in said tube to apply tension to and toentrain said fabric downwardly through said tube, in combination withmeans at each of said feeds for deflecting the fabric away from theinner surface of said tube to change the angular path of said fabric inrelation to said tube during said fabric entraining movement, said lastmentioned means being operative during said forward rotation of saidcylinder and comprising a member secured to the inner surface of saidtube over which said fabric is drawn by said flow of air, said memberhaving a high portion positioned on a radial line extending from thecenter of said cylinder through said needles at a point substantiallycoincident with the lowest stitch drawing position of said needles.

2. In a multifeed circular knitting machine having a needle cylinderadapted for rotary movement in a forward direction, needles in saidcylinder, means for feeding yarn to said needles at each of said feeds,a cam at each of said feeds for operating said needles through stitchdrawing movements during rotation of said cylinder in a forwarddirection to form tubular stocking fabric, a stationary tube within saidcylinder, and means for creating a flow of air through said tube toapply tension to and to entrain said fabric downwardly through saidtube, in combination with means at each of said feeds for deflecting thefabric away from the inner surface of said tube to change the angularpath of said fabric in relation to the inner surface of said tube duringsaid fabric entraining movement, said last mentioned means beingoperative during forward rotation of said cylinder and comprising amember secured to the inner surface of said tube over which said fabricis drawn during said entraining movement, said member having a highportion the leading edge of which is positioned on a radial lineextending from the center of said cylinder through said needles at apoint substantially coincident with the lowest stitch drawing positionof said needles.

3. In a multifeed circular knitting machine having a needle cylinderadapted for rotary movement in a forward direction, needles in saidcylinder, means for feeding yarn to said needles at each of said feeds,a cam at each of said feeds for operating said needles through stitchdrawing movement during rotation of said cylinder in said forwarddirection to form tubular stocking fabric, a stationary tube within saidcylinder, and means for creating a How of air to apply tension to and toentrain said fabric downwardly through said tube, in combination withmeans at each of said feeds for deflecting the fabric away from theinner surface of said tube to change the angular path of movement of thefabric in relation to the inner surface of said tube during said fabricentraining movement, said last mentioned means being operative duringforward ro tation of said cylinder and comprising a member secured tothe inner surface of said tube over which said fabric is drawn duringsaid entraining movement, said member having a high portion the leadingedge of which is positioned on a radial line extending from the centerof said cylinder through said needles at a point substantiallycoincident with the lowest stitch drawing position of said needles, andan inclined portion for camming said fabric from said inner surface ofsaid tube to the leading edge of said high portion of said member.

References Cited in the file of this patent UNITED STATES PATENTS2,641,117 Desmonds June 3, 1953 2,844,952 Wawzonek June 29, 1958 FOREIGNPATENTS 202,394 Australia July 5, 1956 1,183,041 France Jan. 26, 1959

